The Igκ Gene Enhancers, E3′ and Ed, Are Essential for Triggering Transcription

The mouse Igκ gene locus has three known transcriptional enhancers: an intronic enhancer (Ei), a 3′ enhancer (E3′), and a further downstream enhancer (Ed). Previous studies on B lymphocytes derived from mutant embryonic stem cells have shown that deletion of either Ei or E3′ significantly reduces Igκ gene rearrangement, whereas the combined deletion of both Ei and E3′ eliminates such recombination. Furthermore, deletion of either E3′ or Ed...